zemi no ato, kenkyuusitu de kyouzyu ni situmon wo simasita.

ゼミ is short for ゼミナール, from the English/German-based word seminar. In Japanese university contexts, it often means a small seminar class, lab group, or academic discussion group led by a professor.

So here, ゼミのあと means after the seminar or after my seminar class.

In ゼミのあと, the の links the noun ゼミ with あと.

• あと means after
• When あと follows a noun, you usually connect them with の

So:

• ゼミのあと = after the seminar
• 授業のあと = after class
• 仕事のあと = after work

This is a very common pattern:
[noun] の あと = after [noun]

で marks the place where an action happens.

In this sentence, the action is 質問をしました (asked a question / asked questions), and that action happened in the professor’s office / laboratory / research room, so Japanese uses で.

• 研究室で = in the lab / in the office / in the research room

Compare:

• 図書館で勉強しました。 = I studied at the library.
• 教室で話しました。 = I talked in the classroom.

So で answers the question where did the action take place?

に marks the target or recipient of the action here.

The question was directed to the professor, so Japanese uses に:

• 教授に質問をしました = asked the professor a question

This is similar to how に is used with verbs involving giving, telling, showing, or speaking to someone:

• 先生に聞きました。 = I asked the teacher.
• 友だちに話しました。 = I spoke to my friend.
• 母に手紙を書きました。 = I wrote a letter to my mother.

So here, 教授に means to the professor.

を marks the direct object of the verb.

Here, the thing being done is 質問をする, which is a very common expression meaning to ask a question or to ask questions.

So:

• 質問 = question
• 質問をする = to ask a question / ask questions

Even though English often uses the verb ask, Japanese frequently uses a noun + する combination instead.

Japanese often expresses actions with suru-verbs, which are nouns plus する.

• 質問 is a noun meaning question
• 質問する functions like a verb meaning to ask a question

So:

• 質問をします = ask a question / ask questions
• 勉強をします = study
• 運動をします = exercise

Japanese does have other verbs that can translate as ask, such as 聞く or 尋ねる, but 質問をする is extremely common and sounds natural in academic contexts like talking to a professor.

It can be either, depending on context.

Japanese usually does not mark singular vs. plural as clearly as English does. So 質問をしました could mean:

• asked a question
• asked questions

If the surrounding context does not make it specific, either translation may be fine.

Japanese often leaves out the subject when it is already understood from context.

So even though English usually needs I, Japanese does not have to say 私は here.

The full sentence could be:

• 私はゼミのあと、研究室で教授に質問をしました。

But in normal Japanese, 私は is often omitted if it is obvious who did the action.

This is one of the most common differences between English and Japanese.

A natural breakdown is:

• ゼミのあと = after the seminar
• 研究室で = in the office/lab
• 教授に = to the professor
• 質問を = a question / questions
• しました = did / asked

Japanese often puts time expressions earlier and puts the verb at the end.

So the structure is roughly:

[time] [place] [person affected/target] [object] [verb]

This is very normal Japanese word order.

Not in this sentence if you want the same meaning.

• 研究室で is correct because it marks where the action happened
• 研究室に would usually suggest movement toward or existence in a place, not the location of an action like asking

And:

• 教授に is correct because the professor is the target/recipient of the question
• 教授を would make the professor the direct object, which does not fit 質問をする

So the particles here are doing different jobs:

• で = where the action happened
• に = to whom
• を = what was asked/done

教授 specifically means professor, not just any teacher.

Japanese has several words for teacher-related roles:

• 先生 = teacher; also used for doctors, professors, etc.
• 教授 = professor
• 教師 = teacher, especially in schools

So 教授に質問をしました sounds specifically like asking a professor, which fits well with ゼミ and 研究室 in a university setting.

研究室 literally means research room, but the best English translation depends on context.

It can mean:

• lab
• laboratory
• professor’s office
• research office
• seminar room/lab room in a university department sense

In many Japanese universities, a 研究室 can be more than just a science lab. It may refer to the professor’s academic office area or the research group’s room.

So in this sentence, a natural translation might be:

• in the professor’s office
• in the lab
• in the research room

depending on the situation.

Because the sentence is describing a completed action:

• しました = did
• 質問をしました = asked a question / asked questions

The plain present/future polite form would be:

• 質問をします

But since the event happened after the seminar and is being reported as something that already took place, しました is used.

Yes. It uses the polite ます form:

• する → します → しました

So the sentence is polite and appropriate for general conversation, classroom use, or writing about what you did.

It is not super formal or stiff, but it is definitely more polite than the plain form:

• polite: 質問をしました
• plain: 質問をした

Yes, that is grammatically possible.

Japanese word order is more flexible than English as long as the particles make each role clear. So both of these are understandable:

• ゼミのあと、研究室で教授に質問をしました。
• ゼミのあと、教授に研究室で質問をしました。

However, the original order may sound slightly more natural because it keeps 研究室で close to the action and presents the setting before the target.

So the original sentence is a very natural choice.